This invention relates to intrauterine drug delivery devices. More particularly, the invention relates to drug delivery attachments for an intrauterine device (IUD) that is an existing, substantially stable, nonmedicated platform, and to methods and apparatus for making and applying the attachments.
Intrauterine devices are known that provide a system for timed release, local administration of drug. For example, IUD's having a drug-releasing erodible outer layer or partial covering have been suggested for delivering a drug to the uterus. In one example of the foregoing, it has been suggested that a small section of a Lippes loop be coated with drug distributed in an erodible polymer. In another example, a sleeve of bioerodible material, having a contraction inducing drug distributed therein, is attached to an IUD that is not a stable platform, but is especially constructed to deteriorate and be expelled.
IUD's partly or entirely formed with medicament-containing silicone rubber have been suggested to provide timed release of the drug in utero. In one example, an IUD includes a tube enclosing a drug and closed by silicone rubber for release of the drug through the silicone rubber. In another example, a resilient, stainless steel member is entirely encased within silicone rubber which can carry a progestogen. In this case, the internal stainless steel member is a flexible, wirelike device that permits the IUD to be collapsed for insertion and to flex to a normal, expanded condition when in place. On the other hand, hollow IUD's containing contraceptive drugs are known. Inside, these contain the drug in a solid or liquid medium. The drug release rate is controlled by the drug permeable walls of the device. A large number of materials for the walls of such devices have been proposed and these include silicone rubbers. Other IUD's of both room temperature and low temperature vulcanizing silicone rubbers with a contraceptive drug distributed therein have been described.
Because room temperature vulcanizing (RTV) silicone rubbers have been found to lack strength necessary in many applications, fillers are added for reinforcement. The fillers in RTV silicones have been determined to be undesirable in drug release articles, however. The fillers, it is said, adversely affect the release of the drug. For this reason, the low temperature vulcanizing (LTV) silicone rubbers have been recommended for the base or carrier material in drug release devices.